This application is related to co-pending application Ser. No. 252,449 filed Apr. 9, 1981 which discloses narrow-band filters which absorb radiation at a selected frequency and transmit optical radiation at other frequencies within a selected frequency band.
Co-pending application, Ser. No. 252,449, describes a narrow-band filter for absorbing radiation from a carbon-dioxide laser with a wavelength of 10.59 microns comprising an alkali-halide crystal having optical incidence and transmission surfaces and having an impurity of approximately 1 atomic percent perrhenate ion or chromate ion. It was suggested that suitable alkali-halides included mixtures of sodium bromide, potassium bromide and lithium bromide.
It is an object of the present invention to provide a narrow-band absorption filter for carbon dioxide radiation in the 9.2-10.8 micron region.
It is further an object of the present invention to provide a narrow-band absorption filter for carbon dioxide laser radiation at 10.59 microns
It is further an object of the present invention to provide a narrow-band absorption filter for carbon dioxide laser radiation at 9.28 microns.